COVID-19 pandemic-related decreases in hand, foot, and mouth disease and scabies: A retrospective study
Authors: Ania Stolarczyk, Julie Ryan Wolf, Alice Pentland
Journal: Journal of the American Academy of Dermatology (2023)

To the Editor: Communicable skin diseases (CSDs) like hand, foot, and mouth disease (HFMD) and scabies rely on close human contact by skin-to-skin and airborne transmission, respectively.1Bhagavatula M. Powell C. Common superficial skin infections and infestations.Paediatr Child Health. 2011; 21: 132-136Abstract Full Text Full Text PDF Scopus (5) Google Scholar The COVID-19 pandemic led to societal changes including school shutdowns and social distancing suggesting possible effects on diagnosis of CSDs. A recent study by Bonanno et al showed a decrease in pediatric and adult scabies in North Carolina during the pandemic.2Bonanno M. Lee O.S. Sayed C. Decreases in scabies and lice cases among the pediatric and adult populations during COVID-19.Pediatr Dermatol. 2022; 39: 737-739Crossref PubMed Scopus (6) Google Scholar However, there are no studies on the effect of the COVID-19 pandemic on HFMD from the United States. A large study from China noted pandemic-related kindergarten closures produced a 52.9% decrease in HFMD cases, leading to delayed HFMD peaks typical in the summer and early fall.3Zhao Z. Zheng C. Qi H. et al.Impact of the coronavirus disease 2019 interventions on the incidence of hand, foot, and mouth disease in mainland China.Lancet Reg Health West Pac. 2022; 20100362Google Scholar To evaluate trends in CSDs during the COVID-19 pandemic, we conducted a single-center retrospective review of cases for pediatric and adult patients with a new diagnosis of HFMD, scabies, or tinea versicolor (TV) between January 2018 and December 2022. TV served as a control condition as it is ubiquitous in the environment and does not rely on human contact for transmission.4Velegraki A. Cafarchia C. Gaitanis G. Iatta R. Boekhout T. Malassezia infections in humans and animals: pathophysiology, detection, and treatment.PLoS Pathog. 2015; 11e1004523Crossref PubMed Scopus (158) Google Scholar Monthly cases from 2018 to 2019 were averaged for each disease and termed "baseline" to represent the prepandemic period. Tukey's multiple comparison test evaluated the mean monthly count between each year. All statistical tests were performed at significance level 0.05. A total of 4419 cases corresponding to 4140 unique patients met the inclusion criteria for our study. Scabies cases were significantly less in 2020 compared to baseline (P = .024) (Table I). Interestingly, scabies cases remained low for 2021 and 2022 compared to baseline (P = .001). There were no significant differences in HFMD or TV over the study period. However, student's t-tests revealed significant decline in HFMD cases in 2020 compared to baseline (P = .005) and an increase in HFMD cases in 2021 compared to 2020 (P = .032). The increase in HFMD cases in 2021 could be associated with decreased social distancing and phased reopening of Rochester suburban area and city school districts (Fig 1). There were no significant differences in race, ethnicity, age, gender, zip code, or department of diagnosis by year (Supplementary Table I, available via Mendeley at https://doi.org/10.17632/h2bx9cf7ms.1). Unlike scabies and TV, most cases of HFMD affected the pediatric population which is consistent with the known epidemiology of the disease.3Zhao Z. Zheng C. Qi H. et al.Impact of the coronavirus disease 2019 interventions on the incidence of hand, foot, and mouth disease in mainland China.Lancet Reg Health West Pac. 2022; 20100362Google ScholarTable ICases of hand, foot, and mouth disease, tinea versicolor, and scabies by yearBaseline202020212022HFMD486.558517438TV290.5288321258Scabies250187∗P < .05 compared to baseline.150∗P < .05 compared to baseline.148∗P < .05 compared to baseline.HFMD, Hand, foot, and mouth disease; TV, tinea versicolor.∗ P < .05 compared to baseline. Open table in a new tab HFMD, Hand, foot, and mouth disease; TV, tinea versicolor. Our study provides unique insights on the impact of social distancing measures on the transmission of CSDs. In 2020, masking, increased handwashing, stay-at-home orders, and limited health care utilization for nonlife-threatening conditions may have reduced scabies cases. In our study, the reopening of schools coinciding with an increase in HFMD cases is an expected trend secondary to increased opportunity for nonfamilial person-to-person transmission. The classroom setting represents a socially dense environment in which HFMD can be easily transmitted amongst young children by contact with contaminated hands and toys.3Zhao Z. Zheng C. Qi H. et al.Impact of the coronavirus disease 2019 interventions on the incidence of hand, foot, and mouth disease in mainland China.Lancet Reg Health West Pac. 2022; 20100362Google Scholar The persistent reduction in scabies cases from 2020 to 2022 compared to baseline may reflect long-standing pandemic-related societal changes, such as increased remote work.5Phillips S. Working through the pandemic: accelerating the transition to remote working.Bus Inf Rev. 2020; 37: 129-134Google Scholar The current study suggests that social distancing measures and school closures instated during the COVID-19 pandemic had a profound impact on the transmission of CSDs. None disclosed.